Flexible metallic tubing.



W. BERRYMAN &"A. REDGRAVE. FLEXIBLE METALLIC TUBING. APPLICATION FILEDDBO. 24, 1910.

1,064,432,, Patented June 10,1913

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int-34,432.

Specification of Letters Patent.

Patented June 10,1913.

- To all whom 2'5 may concern:

Be it known that we, WILIJAM BERRYMAN, engineer, and ARTHUR RnncnAvE,engineer, 'both subjects of the of Great Britain, both residing at TheUnited Flexible Metal- 110 Tubing Company Limited,'Penders End, in thecounty of hfid'dlesex, England, have jointly inventedcertain newandusefuhlmprovements' in Flexible Metallic Tubing, of which thefollowing is a specification.

Flexible metallic tubing is manufactured byyhelically coiling a strip ofmetal corrugated in various forms but in such a man nor that thesuccessive convolutions, when to or in the course of the coiling of thetube such a manner thatwhen coiled there are one or more additionalchanneled convolutions-provided between the actual convolutions theedges of which serve to interlock the coiled strip, in forming theadditional convolutions of a shape similar to that of the interlockingconvolutions, and in parallelism therewith.

In the accompanying drawings Figure,:, l is a sectional view of thespirally wound tube showing one such additional convolution and Fig. 2 asnnllar' View showing a plurality of such additional convolutions.

Hitherto such tubing has. been manufactured from a strip of metalcorrugated so that ,it consists of two channels a and 5 turned inopposite directions, the one channel a having its convex side toward theexterior of the tube and the other channel Z).

.liayifig its concave side toward the exterior. This strip beingspirallywound, the outer edge-a otthe next" convolution is laid in thechannel 1).. A strip or band'c' of packing material such as india rubberis also wound at the same time with tllfifitl'll), the said packingbeing inclosed between the two adjac'ent overlapping edges o f themetalstrip,

thus forming a tight joiiit, while at the same time giving a certainflixibility to the tube.

The present invention consists in so corrugating thestrip, that inaddition to the interlocking convolutions there are one or moreadditional channeled convolutions such as one at (Fig. 1) or two outerconvolutions d, d and two inner convolutions d (Fig.

that the greater width of strip employed causes a greater length of tubeto be formed with each coiling, thus expediti g the'manufacture whilethe intermediate corrugations preserve the strength. In addition tothis, packing is necessary only at greater distances apart, thuslessening the quantity required, sothat the cost 'of manufacture isconsiderably reduced. f

Although the invention is shown. as applied to one particular formationof strip for boiling a tube, it {is equally applicable toemany otherfermationsof strips used for manufacturing flexible metallic tubing inwhich the coils are interlocked. Having thus described the nature of thsaid invention and the best 'means we know of carrying the sameinto'practical efiect, we claim V 1. A flexible metal tubing consisting of ametal strip helically coiled to form a series edge, andan outwardlydirected and simi: larly shaped channel on the other edge parallel withthe first channel, so that the ehan neled edges of two adjoiningconvolutions of the strip interlock, each convolution also having aninwardly directed channel'and an outwardly directed channel between theinterlocking channels and parallel th e-' with, and a packing striseated in the interlocking channels; so stantially as described. w 7 b l2..A flexible metallic tubing, consisting of of convolutions,saidastriphaving an inwardly directed channel formed on one larly shapedchannel on the other edge pan allel with thefirstlchannel, so that theChenneled edges of two-adjoining convolutions having a plurality: ofinwardly directed 2) or there may beanore. 1 It will be seen 7 a metalstrip helically coiledto-form a series of convolutions, said striphaving -an inwardly di'rected channel formed on one edge, and an"outwardly directed-and simis otthe. strip interlock,each-convolutionalso g emme channels ancla plurality of cutwei'dlly dinames to thisspecification in the'presence meted channels of similar shape in the in:of two subscribmg Witnesses. terloching channels and parallel therewith,

Y WILLIAM BERRYN .the last mentioned channels bemg located 5 between theinterlocking channels, and & ARTHUR BEDGRAVE' packing strip seated inthe interlocking Witnesses: channels; substantially as described. JOSEPHMILLARD,

. In testimony whereof we have signed our WALTER J. SKERTEN.

